Engine pressure regulator



\ ril'i1,1950

c. H. JORGENSEN ET AL 2,50 7

ENGINE PRESSURE REGULATOR l3 Sheets-Sheet 1 Filed June ll 1945 tinvumwkafi WM 4% m m INVENTORS mu A! BY Ap 1950 c. H. JORGENSEN EI'AL2,503,274

ENGINE PRESSURE REGULATOR Filed June 11, 1945 3 Sheets-She 2 Y OPEEfl7'60 SPEED MOD/FIEB Ea KN 3% INVEN 0R5 Maw/2 4 $5 BYZiwzma M E v April1950 c. H. JORGENSEN EI'AL ,503,27

ENGINE PRESSURE REGULATOR Filed June 11, 1945 13 Sheets-Sheet 3 k:lNVE;I}'OR5 I GYM fill/Ma r 54 ATTORNEYI/ April 1950 c. H. JORGENSENEI'AL 2,503,274

ENGINE PRESSURE REGULATOR Filed June 11, 1945 I 13 Sheets-Sheet 4 l vINVENTORS (7 7 I I M BY: 6? JW /7 /7 gdmmwwzlv M H A6 55 ATTORNEYA:

April 1950 c. H. JORGENSEN ETAL 2,503,274

ENGINE PRESSURE REGULATOR Filed June 11, 1945 13 Sheets-Sheet 5INVENTORS i 0 WW f BY dam WM! 13 dgou-wvjj/l ATTORNEYJ/ Ap 11, 1950 c.H. JORGENSEN ETAL ENGINE PRESSURE REGULATOR 15 Sheets-Sheet 6 Filed June11, 1945 April 11, 1950 c. H. JORGENSEN EI'AL 2,503,274

ENGINE PRESSURE REGULATOR Filed June 11, 1945 l3 Sheets-Sheet 7 m911/96- mg 7 April 11, 1950 c. H. JORGENSEN ETAL 2,503,274

ENGINE PRESSURE REGULATOR 13 Sheets-Sheet 8 Filed June 11 1945 INVENTORSApril 1950 c. H. JORGENSEN ETAL 2,503,274

ENGINE PRESSURE REGULATOR I 1s Sheets-Sheet 9 Filed June 11, 1945iNVENTQR by 0M fi a TTORNEYAA April 11, 1950 C. H. JORGENSEN ET ALENGINE PRESSURE REGULATOR 13 Sheets-Sheet 10 Filed June 11, 1945A'E'TORN Ema April 1950 c. H. JORGENSEN ETALY 2,503,274

ENGINE PRESSURE REGULATOR l3 Sheets-Sheet 12 Filed June 11, 1945 www ZATTORNEY,

AL Tl TUBE Patented Apr. 11, 1950 ENGINE PRESSURE REGULATOR Clarence H.Jorgenaen and Lawrence C. Dermond, Rochester, N. Y., alslgnorr toGeneral Motors Corporation, Detroit, Mlcla, a

Delaware corporation of Application June 11, 1945, Serial No. 598,788

20 Claim.

This invention relates to apparatus for controlling the intake pressureof a supercharged internal combustion airplane engine. Moreparticularly, the invention relates to control apparatus having amanually operated means for selecting a pressure to be maintained in theengine intake, a device responsive to intake pressure, and a servo-motorunder joint control by said means and device for adjusting the throttlevalve of the engine so as to correct for divergencies of intake pressurefrom theselected pressure. The throttle valve is under manual control aswell as control by the servo-motor to the extent that a safe landingmaybe made in case of failure of control by the servo-motor.

One object of the present invention is to provide that the sum of themanually effected throttle movement and the movement effected by theservo-motor shall bring the throttle to wideopen position at criticalaltitude for all pressure selections in the flight range from minimumcruise pressure to highest pressure. In the disclosed embodiment of thisinvention, this object is accomplished by providing an hydraulicservomotor that is capable of adding to the manually effected movementof the throttle an automatic movement greater than required to bring thethrottle to wide-open position for all pressureselections above minimumcruise pressure, and by providing means responsive to the wide-openingof the throttle for arresting further operation of the servo-motorthrough the use of an hydraulic check or look. e

Other objects of the present invention are to provide for thecoordination of control of the propeller pitch governor with theselection of pressure to be maintained whereby the governed engineorpropeller speeds can be varied with change of pressure selectionaccording to a predetermined schedule, to provide manually controlledmeans for modifying the schedule between certain values -of pressureselection, used for partload operation, by changing the governed speedsof the engine in relation to pressure selection, and to provide fornullifying the efiect of the modifier when the pressure selections areother than for part load, such other pressure selectionsbeing forexample, the selections required for idling or for maximum power. Theseobjects are accomplished in the disclosed embodiment of the invention byan hydraulic servomotor connected with the control member of thepropeller pitch governor, the stroke of the servomotor being determinedby the location of a valve which is positioned by a rotary camcoordinated with the manually operated pressure selecting means. Theaction of the cam is modified by manually controlled means whichoperates to eiIect a movement of the cam laterally with respect to itsaxis as the cam is rotated between certain angular positions.

Another object is to provide for manually rendering inoperative theconditioning of the propeller pitch governor control by the cam in orderthat the pilot may control the governor manually when desired. In oneform of the invention this is accomplished by moving the manuallyoperated member which modifies the schedule of engine governed speedsvs. pressure'selections in a direction opposite that required for itsmodifying function. In another form, this is accomplished by a manuallycontrolled electromagnet. In both forms of. the invention, whenconditioning of the governor control by the cam is rendered inoperative,a spring automatically returns the governor control to a conditioncalled for highest governed speed for purpose of checking the ignitionmagneto.

A further object of the invention is to coordinate the intake pressurecontroller and speed regulator with a means for actuating the speedcontroller of an auxiliary supercharger, for example, one which isdriven by the engine through change-speed gearing capable of beingshifted from low speed to high speed by a control lever. Moreparticularly, an object is to effect the shifting from low speed to highspeed automatically according to a predetermined schedule of alti tudesand pressure selections and to effect automatically, in response to theshift into high gear, an increase of pressure over the selectedpressure, which increase varies according to a predetermined schedule ofselected pressures and pressure increases.

A further object of the invention is to provide control unit having ahousing containing the mechanisms for effecting throttle control jointlyby manual and by servo-motor operations and for effecting thecoordinated control of engine governed speed, the operating parts beingcompletely enclosed except as to certain levers, such as the manuallyoperated lever which operates the throttle valve and selects thepressure, the throttle valve operating lever, the lever which isconnected with the propeller pitch governor control member and the speedmodifying lever. In this connection it is an object to provide agear-shift operating unit which has a housing containing the operatingparts which are completely enclosed except as to the lever connectiblewith the change-speed operating member and a manually operated lever forrendering the unit inoperative at will. The gear-shift operating unitmay be combined with the pressure and speed control unit by joiningtheir housings after making the necessary connections required forcoordinating pressure selection with gear-shift control and forcoordinating shift into high gear with pressure increase.

Further objects and advantages of the present invention will be apparentfrom the following description, reference being had to the accompanyingdrawings, wherein preferred embodiments of the present invention areclearly shown.

In the drawings:

Fig. 1 is a side view of the pressure and speed controller combined withthe gear-shift unit.

Fig. 2 is a view of the side opposite that shown in F18. 1.

Fig. 3 is a plan view of the apparatus shown in Figs. 1 and 2.

Fig. 4 is an end view in the direction of the arrow 4 of Fig. l.

"igs. 5 through 2'! illustrate only the pressure and speed control unit.

Fig. 5 is a sectional view on line 55 of Fig. 4.

Fig. 6 is a sectional view on line 6-5 of Fig. 4.

Fig. '7 is a sectional view on line -11 of Fig. 6.

Fig. 7a. is a continuation of Fig. '1.

Figs. 8 and 9 are views similar to Fig. 6 showing parts in otherpositions of operation.

Fig. 10 is a sectional view on line l8l8 of Fig. 4.

Fig. 11 is an enlarged sectional view on line ||ll of Fig. 10.

Fig. 12 is an enlarged sectional view on line i2-I2 of Fig. 10.

Fig. 13 is an enlarged sectional view on line "-12 of Fig. 12.

Fig. 14 is an enlarged end view in the direction of arrow 14 of Fig. 12.

Fig. 15 is a sectional view Figs. 4 and 19.

Fig. 16 is a sectional view P18. 15.

Fig. 17 is a sectional view Fig. 19.

Fig. 18 is a sectional view 1'18. 19.

Fig. 19 is a sectional view Figs. 15 and 1'7.

Fig. 20 is a sectional view Fi 18.

Fig. 21 is a sectional view Fig. 15.

Fig. 22 is a sectional view P18. 15.

Fig. 23 is a sectional view 1'18. 15.

Fig. 24 is a sectional view on line [5-15 of on line lS-li of on line11-11 of on line l8l8 of on line 13-13 of on line 28-28 ofon line 21--21 of on line 22-22 of on line 23-23 of on line 24-24 of Fig. 6.

Fig. 25 is a sectional view on line 2525 of Fig. 26 is a sectional ViewPics. 6 and 10.

Fig. 2'7 is a plan view of the operating mechanism with the housing insection.

Figs. 28A, 28B, 29 through 33 illustrate the gear-shift operating unit.

Figs. 28A and 28B are similar sectional views on line 2828 of Fig. 3.These views difler with respect to the positions of certain parts.

Figs. 29, 30, 31 and 32 are sectional views taken respectively on lines2823, 38-48, 21-31 and 22-22 of Fig. 28A.

Fig. 33 is a sectional view on line 2342 of P18. 31.

Fig. 34 is a chart showing the mode of operation of the pressure andspeed controller.

Fig. 35 is a chart showing the mode of operation of the gear-shiftoperating unit.

Figs. 36 and 3'? are sectional views similar to Figs. 10 and 15,respectively, and show modified forms of the invention.

Fig. 38 is a fragmentary plan view of Fig. 36.

Fig. 1 shows a housing I to which an end on line 28-25 of cover 2 isattached by screws 2a, to which a side cover 8 is attached by screws 3a,to which either a housing 4 may be attached by screws 4a or to which acover 1 (Fig. 6) may be attached by screws 1a. To the housing 4, thereis attached a side cover 5 by screws 5a and a top cover 6 by screws Go.To the cover 2 (left of Fig. 1) there is attached a bracket 8 by screws8a. Fig. 2 shows bracket 9, integral with housing i, which may beattached to a support 18 by bolts II and nuts 12. (Parts l8, II and I2are indicated in dot-dash-lines in Fig. 2 since they are not a part ofthe unitary structure.) Fig. '1 shows a bracket 14 integral with housingi to which a rod 15 is secured by nuts 16 and 11. Fig. 7a shows that therod 15 has a cup-like spherical end l8 received by a spherical socket ina fixed support 19 and secured thereto by a stud 28 and a nut 2|, therebeing a washer l8a between the nut 21 and the part i8, said washer 18ahaving a spherical under-surface.

The pilot's control lever (not shown) is connected with the controllerby mechanism including a link 25 (Fig. 3 left), a bell-crank lever 28attached to a shaft 21 journalled in a bearing boss 28 integral withbracket 8, a pin 29, adjustable link parts 38, 3i and 32, a pin 33, alever 34 and the main control shaft 35. Shaft 35 is journalled in abearing 38 (Fig. 23) provided by the cover 3 and in a bearing 31provided by the housing i. Shaft 35 drives a lever 38 (Fig. 6) havingstop lugs 39 for engaging adjustable stop screws 48 threaded in housing1.

Lever 38 carries a stud 4| pivotally supporting a roller 42 retained bya washer 43 and a nut 44. Roller 42 is received by a slot 45 in afloating or differential lever 46, so called because its position iscontrolled jointly by the pilot through shaft 35 and lever 38 and by anhydraulic servo-motor. Lever 48 carries a pin 41 connected by link 48with pin 43 on lever 58 attached to shaft 51 journalled as shown in Fig.7 in bearings provided by the housing i and cover 3. Shaft 5|, whichoperates the throttle valve 88, is connected therewith by arm 52 (Figs.1, 4 and 7), adjustable link parts 54, 55 and 58, screw 51, arm 58 andshaft 59 on which valve 88 is mounted.

The lower end of lever 46 (Fig. 7) is bifurcated (Fig. '1) to embrace arod 82 and to receive a pin 6| passing through it. Rod 52 slides in abushinil 63 mounted in a boss 84 integral with housing i and in bushingmounted in a wall of the housing. Rod 82 is attached to a piston 68slidable in a cylinder 61 provided by housing I. A spring 68 urges thepiston 68 right and returns it to normal position shown in Fig. 6 incase of failure of oil pressure.

The oil high pressure line is connected at 18 (Figs. 4 and 24), andpasses through passage 11 closed by cover1 (Fig. 24) and through sidepassage 12 (plugged at 13) and through passage 14 (Fig. 25, plugged at14a) and through passage 15 which crosses passage 18 (plugged at 16a).Passage 15leads to a groove 11 in valve guide 18; and groove 11 isconnected by a plurality of ports 18 with the interior of the guide 13.Guide 18 is received as shown in Fig. 10 in a bore provided by housingi, and is retained by a flange 19a on its right end and by a split-ringwasher 88 against which there bears a spring 81. Guide 18 hasdistributing ports 82 leading into a groove 88 connected by passage 84(plugged at 84a) and passage 85 (Figs. 26 and 8) with the right end ofcylinder 61. Guide 19 has distributing ports 85 tated by the pilotthrough the shaft 35.

leading into a groove 81 connected by passage 08 (lllulged at 83) and bypassages and SI (Figs. 25 and 26) with the left end of cylinder 01.

The distributing ports 82 and 86 (FIg. 10) are controlled by lands 96and 91, respectively, of a valve 96 connected by rod 38, clevis 39 andpin III with a floating lever IOI, pivoted at I02 on a bridge I30 andcarrying a pin I03 connected by link I04 and pin I05 with lever- I06.Lever I06 (Fig. 12) is attached to a hub I01 journalled on rod I00having aligned cylindrical pintles I09 which are eccentric to the axisof rod I08. Pintles II! are Journalled in ball bearings I I0, supportedby bosses III provided by-housing I. Hub I01 has a slot I I2 throughwhich there extends a rod 15 III. threaded into rod I08 and having aneye II4. Rod II3 provides a lever for rotating the rod I08 for a purposeto be described. Lever I06 carries a pivoted roller I for engaging apressure selecting cam I which is manually ro- The roller I20 is urgedtoward the cam I2I by a spring I22 connecting lever I06 with a screw-eyeI23.

The valve 95 to which. lever I M is connected is under joint control bythe cam I2I and by a 25 device responsive to engine intake pressure.Fig.

5 shows that the-bridge I30, which supports pin I02; connects theadjacent end plates I3I and I33 of bellows I 32 and I 34 having remoteend plates I35 and I36. Plate I35 is attached to hous- 3() ing I; andplate I36 has a central boss I31 received by a tubular boss I38 in cover2. Boss I31 is urged against an adjustable plug I39 by the springs whichtend to expand the bellows.

By turning the plug I39 the correct initial loca- 35 tion of pin Hi2 canbe established. Bellows I34 is evacuated. Bellows I32 is connected bypassages I40, MI and I42 with a pipe (not shown) which is threadedlyconnected at I43 and with the engine intake at the manifold or at theout- 4U let of the housing of the engine stage supercharger. Thecompression spring I44 in bellows I32 is confined between plate I3I anda ring I45 carried by annular plate I35. Compression springs I46 and I41 within bellows I34 are con- 45 fined between plates I33 and I36 Theexternal areas of the bellows are equal so that the location of pin I02will be controlled only by engine intake pressure. The springs I44, I46and I41 are so constructed and calibrated that pin I02 50 is positionedin a predetermined relation to intake pressure in bellows I32. Thus thethrottlevalve-operating servo-motor is under joint control by thepressure selecting cam I2I and by engine intake pressure. 5 Fig. 34 isbased on 66 of rotation of lever 38. The right border of Fig. 34indicates degrees of opening of throttle from idle position. Curve P-Qrepresents the throttle movement which can be effected by moving thelever 38 which is manuc0 ally operated by the pilot when selecting thepressure to be maintained. The left border of Fig. 34 indicates manifoldpressure. Curve GH shows the manifold pressures which can be obtained bymovement of the throttle 60 through 05 manual movement of lever 38 (Fig.6) while the piston 61 remains at the right end of cylinder 61. Themanual movement of the throttle and pressure resulting from the manualmovement of the throttle are such that a take-off could be made and asafe landing could be effected although the throttle-valve servo-motorfailed to operate. Curve J-.KL--M shows the pressures selected by camI2I for various positions of lever 38. .The portion to the left of theminimum 15 cruise" line is not effective during flight. Selectedpressure J. at the "engine-idle" position of lever 38 is negative 17" Hgabs. which is effective, in case of a punctured aneroid bellows I34, togive a net positive pressure of 29.6" less 17" equals 12.6" only alittle above the 10", point (3 on line G-H. Therefore the engine can becontrolled for safe-landing by the pilot's control lever acting throughthe shaft'35 and lever 38 on the throttle valve 60, while thethrottle-valve servo-motor remains non-operative.

In order that the pressures selected for minimum cruise or greater maybe maintained, the servo-motor piston 66 is caused to move toward theleft to effect whatever additional opening of the throttle 60 isrequired to correct for any divergencies between intake pressuretransmitted to bellows I32 and the selected pressure. For

example, assume that the pilot wishes to take 0 off." Lever 38 is movedfrom the position shown in Fig. 6 to that shown in Fig. 8 which is its55 position. A pressure of 44.5" Hg abs. has been selected. The valvehas been moved right in Fig. 8 to connect ports 18 and 82 and piston 66starts moving left toward the position in Fig. 9 to increase thethrottle opening by whatever amount is required to brin the intakepressure up to the selected pressure. When these pressures balance thevalve 95 returns to the equilibrium position shown in Fig. 9 andmovement of the piston 66 toward the left ceases. As the altitudepressure decreases, the piston 66 continues moving left to increase thethrottle opening. Finally the throttle becomes wide open as indicated bya point on line E-F (Fig. 34) indicating substantially wide-openthrottle. The altitude at which the throttle must be wide-open tomaintain the selected pressure is called the critical altitude for thepressure selected. At higher altitudes the pressure diminishes unlessthere :be an auxiliarysupercharger whose speed can be increased tocreate more pressure.

Fig. 9 shows the status when wide open throttle has been obtained for apressure selection of 44.5" Hg. Bellows I32 has expanded and bel'- lowsI34 has contracted as the result of the pressure in bellows I32. Valve95 is in balanced position. Critical altitude for a pressure selectionof 44.5 Hg has been reached. The plane ascends still higher and altitudepressure drops. The engine pressure falls and pin I02 is urged towardthe right in Fig. 9 and tries to move valve 95 right to cause the piston66 to move left of the position shown in Fig. 9, in the effort to 0b- 5tain greater throttle opening. But that would avoil nothing because thethrottle is already wide open.

To prevent such movement of the piston 66 I to the left of the positionshown in Fig. 9, an

hydraulic check or lock has been provided. The movement of lever 50 tobring the throttle 60 to wide open position causes a pin I50 to bearagainst a lever I54 having an ear I55 carrying a. screw I56 which iscaused to engage the valve 95 and to hold it in equilibrium position.Therefore when the throttle 60 is wide open, no oil can pass into or outof the cylinder 61 and the piston 66 is hydraulically locked in thatposition at which it arrived when the throttle 60 was brought intowide-open position. Lever I54 is loosely supported by the shaft 5I; andit is urged toward the pin I50 by a spring I52 having an end I5I bearingagainst the pin I50 and an end I53 bearing against the lever I54. Asshown in Figs. 6 and 10, the spring I52 urges the lever I54 toward plate1, while pin I59 may move away from lever I54.

The reason for providin a servo-motor with piston travel greater thanrequired for wide-open throttle a 44.5" Hg pressure selection will beapparent from Fig. 34, which shows that the required servo-motormovement of the throttle is. for various pressure selections, thedistance vertically between line DEF and line P-Q. These distancesincrease as the selected pressures decrease from take-off" or 44.5 Hg.Therefore the available servo-motor movement of the throttle must begreater for lower pressure selections. The geometry of the throttleoperating mechanism is such that when the servo-piston moves full-strokeleft, the throttle will be full-opened at a pressure selection of about30" Hg which is slightly above minimum cruise pressures. Between the and25 positions of lever 38 the maximum possible throttle opening decreasesslightly as indicated by the line D-E. It is apparent that the throttlecan be brought to wide-open position for any pressure selection usedduring flight.

Experience in the use of the apparatus reveals that the throttle travelis. actually about two degrees greater than that calculated beforemotion is arrested by the hydraulic lock. Therefore. it the requiredthrottle movement is 72 the mechanism is calculated to ive 70 throttlemovement as indicated by EF on the 70 line inFig. 34.

Fig. 2 shows a shaft I69 attached to a, lever I5I having a slot I63 forreceiving a bolt I62 which may be secured in the required position alongthe slot by tightening a nut I62a. Bolt I52 provides for making aconnection with a linkage (not shown) connected with the control leverof a propeller pitch governor. Lever I9I is movable from thefull lineposition to the position I6Ia to change the governed speed of the enginefrom minimum to maximum; Shaft I69 (Figs. 15 and 22) is mounted inbearings I62 and I56 and carries a lever I61 secured by tightening ahub-clamping screw I68. A pin I69 connects the lever I61 with a linkI19, having a hub I19a (Fig. 21) connected by pin I1I with a tubularpiston rod I12 attached to a piston I13 slidable in a cylinder I14provided by housing I. Piston rod I12 is slidable in bushings I14a andi140, bushing I14a being secured in the cylinder I14 by a nut I141).Piston I13 has'a circumferential groove I15 which receives oil-underpressure from a passage I16 (Fig. 12) connectible with a port I11 (Fig.25) in a valve I18 operated by a. lever I19 and rotatable in a bore I89.Fig. 25 shows port I11 connected with passage 14. Valve I18 has anotherport I8I and I94.

disconnecting passages 14 and 16 from valve I19 and causing passage I16(Fig. 23) to be connected with drain passage I82 through the bore invalve I18. This renders inoperative the servo-motor for actuating thelever I69 and permits manually controlling the propeller pitch governor.Spring 239 (Fig. 15) will return the piston I13 to its extreme leftposition and lever I6I (Fig. 2) will be moved to position I6Ia whichwill condition the propeller governor for highest speed required formagneto check. The valve I18 may be yieldingly retained in one or moreof its positions by providin a; detent groove or grooves I85 forreceiving a ball I86 urged toward the groove by a spring I81 retained bya plug I88. By plugging hole 15, valve I18 can be used to disconnect thethrottle-valve operating servo-motor from pressure oil passage H and toconnect said motor with drain. This should be done in order to preventscape of oil in case of damage to the servo-motor.

Fig. 15 shows that passages I99 connect groove I15 with diametricallyopposite grooves I9I in rod I12 and that holes I92 connect these grooveswith the space between lands I93 and I94 of a valve I95 slidable withthe rod I12. Figs. 7 and 19 showv that land I94 controls ports 224leading to diametrically opposite grooves 228 (displaced from groovesI9I); and that grooves 225 are connected by holes 228 with the left sideof piston I13. Figs. 18 and 20 show that land I93 controls ports 223leading to diametrically opposite grooves 225 (displaced 60 from groovesI9I and 228) and that grooves 225 are connected by holes 221 with theright side of piston I13. It is apparent that the piston I'll willfollow the valve I95 and will stop with its ports 223 and 224 blocked bythe valve lands. If valve I95 moves left to uncover ports 223 and 224,pressure oil enters the right end of cylinder I14 through ports 223,grooves 225 and holes 221, while oil in the left end of the cylinderdischarges through holes 228, grooves 226 and ports 224 and out theright end of rod I12. The piston I13 moves left the distance which valveI95 had moved left because that is the distance required to align ports223 and 224 with valve lands I93 If valve I95 moves right from theposition of equilibrium last mentioned, ports 223 and 224 are againuncovered by the lands I93 and I94 displaced to the right. Pressure oilenters the left end of cylinder I14 through ports 224, grooves 226 andholes 228 to cause piston I13 to move right while oil is beingdischarged from the right end of cylinder I14 through holes 221, grooves225 and ports 223 and out through the left end of rod I12. The rightmovement of the piston I13 connectlble either with passage 16 or with adrain passage I82. Passages 14 and 16 are connected with oil pressurepassage 1I. When the valve I18 is in the position shown in Fig. 15, thepiston groove I15 receives pressure oil. A limited rotary movement ofvalve I18 may take place while pressure oil still flows to groove I15.This movement in a counterclockwise direction in Fig. 15, or clockwisein Fig. 2, may take place until arrested by a stop provided by ashoulder I190. of an annular boss I19c (provided byhousing I) which isengaged -by a lug I19d (Fig. 2). counterclockwise movement of lever I19(Fig. 2) is arrested by the engagement of the lug "M with anothershoulder I19b of the annular boss I19c. This counterclockwise movementin Fig. 2 willbe clockwise in Fig. 15 and results in is equal to thedisplacement of valve lands I93 and I94 to the right of ports 223 and224.

The valve I is positioned by a screw I96 against which valve I95 isurged by a spring I91 confined by a cup I98 bearing against link I19.Screw I96 is carried by an ear I99 of a lever 299 and is secured inadjusted position by a nut I980. Lever 299 has a hub 29I (Fig. 16)journalled on a stud 292 carried by housin I and retained by washer 293and a nut 294 secured by a pin 295. Lever 299 carries a stud 298supporting a roller 299 for engaging the cam surface 2I9a of a cam plate2I9 pivoted at 2 on an arm 2I2 having a hub 2 I3 fixed to the maincontrol shaft 35. Plate 2I9 is pulled against a strut 2I6, extendingfrom hub 2 I3, by a spring 2 I 5 connecting plate 2I9 with an eye 2extending from hub 2I3. When the shaft 35 is rotated clockwise to selectthe preswith passage I82.

ment toward the left.

sure denoted by J--K--L M (Fig. 34) the cam 2I8a so controls valve I95,piston I93, lever I61, shaft I68 and lever I6I as to cause the enginegoverned speed to vary according to the schedule denoted by A--BC (Fig.34) which is the schedule for a fully loaded plane.

For cruising with less than full load, the speed schedule may be reducedas indicated by lines A1-B, A2-B, Az-B, A4-B, As-B or any schedulebetween. The full load schedule can be reduced by moving clockwise (Fig.2) a lever 243 attached to a shaft 242 and connected by link 245 and pin246 with lever I19 which controls .valve I18, which continues to connectthe oil pressure duct H with the piston groove I durin this movement. InFig. 15, shaft 242 is rotated counterclockwise to move a pin 248 carriedby arm 24I into engagement with a cam surface 2 I 8b of plate 2 I 8which moves down to cause lever 288 to move right a distance dependingon the extent of downward movement of pin 248. Valve I95 can follow thescrew I96 under the action of spring I91 at least until stopped by theengagement of a notched collar 23I provided by the valve with asplit-rin 232 seated in a groove adjacent the right end of piston rodI12. Therefore the piston I13 will not begin to move left to rotatelever I61 from its position of lowest speed control until the controllever I38, has moved further than from about its 11 position. The

greater the distance plate 2I8 is moved downwardly from its normallocation the greater will be the distance that the lever I38 must bemoved before piston !13 starts to move left, as indicated by. points A1,A2, A3, A4, A5 (Fig. 34). The portions of cam surface 2I8a near to thepivot 2| I are affected but slightly, hence the schedules begun at A1 toA5 return to the normal schedule at B when the lever 33 moves to its 40position. The normal schedule is resumed for pressure selections above38.6 Hg, for example.

When lever 243 is moved counterclockwise (Fig. 2) until lug I19d engagesstop shoulder I19b, valve I18 rotates to close passages 94 and 16 andmeans: passage I16 (Fig. 23) to be connected This removes the hydraulicpressure tending to move the piston I13. Spring 238 returns the piston I13 to a position calling for highest governed engine or propeller speedrequired for checking the ignition magneto. 1' he pilot can actuate thepropeller pitch governor control and piston I13 follows along, the oilin the left end of cylinder I14 being discharged as piston I13 movesleft relative to valve I95. The discharge is through'holes 228 (Fig.1'1), grooves 226, ports 224, holes I92, hole I98, groove I15, passageI16, valve port I81 and outlet I82 into the housing I. Spring 238assists piston move- As piston I83 is moved right during manualoperation of the propeller pitch governor control, oil in the right endof cylinder I14 can escape through holes 221, grooves 225 (Fig. 18) andports 223 and out the left end of piston rod I12.

The gear-shift operating unit will now be. described with reference toFigs. 28A- B, 29 through 33. This unit provides, exterior of housing 4,a lever 258 (Fig. 31) to be connected in any suitable manner with thegear-shift operating member of the transmission gearing which connectsthe engine with an auxiliary supercharger. Lever I by a lever 256carrying a stud 251 having a part '258 is attached to a shaft Ijournalled in ball 258 which .is movable between motion limiting screws259 and 215, the latter being locked by a nut 216.

A spring 268 connects stud 251 with a stud 26I on lever 262 attached toshaft 263 journalled in bearings 265 and retained by snap-ring 284. Stud26I receives a spacer 266 and a link-281 connected as shown in Fig. 28Awith a pin 268 carried by a clevis 269 attached to a piston 218 slidablein a cylinder 2' provided by housing 4. A spring 212 which urges piston218 toward the right is retained by a washer 213 and a snap-ring 214.The normal position of the arm 256 is shown in Fig. 28A, wherein itsstud part 258 is urg against screw 215 by the spring 268.

Pressure oil for operating the piston 218 comes through passage 288(Fig. 32) which becomes connected with the pressure oil passage H ofhousing I when housing '4 is attached thereto. in place of cover 1.Passage 288 leads to duct 28I and thence to a groove 283 in a valveguide 282 urged against a seat 282s by a spring 282a. Groove 283 leadsto ports 284 and thence to the space between the lands 29I and 292 of avalve 298. Valve land 292 controls ports 285 leading to groove 286connected by ducts 281 and 288 with cylinder 21I. Valve 298 is connectedby rod 293, clevis 294, stud 295 with a lever 296. Lever 296 is pivotedat 291 and is provided with a slot 298 and with a pad 299 (Fig. 30)against which there bears a spring 385 retained by a stud 386 to causethe pad 299 to engage a cam 388 provided by a shaft 38I journalled inbearings 382 and 383 (Fig. 31) and restrained against axial movementtoward the left by a washer 38Ia and a pin 38Ib.

Shaft 38I is operated by arm 38 (Fig. 28A) by providing it with a stud3I3 for receiving a link 3I2 connected by studs 3 with a cam plate 3l8attached to shaft 38!. Cam plate 3I8 has a cam slot 3I5 for receiving aroller 3| 6 journalled on a stud 3I1 carried by lever 3I8 having a hub3I9 (Fig. 31) journalled 0n stud 251. Arm 3I8 has a lug 328 engageablewith a, lug 32I of an arm 338 connected by stud 33I '(Fig. 31) and alink 332 with the rod II3 which, as shown in Fig. 13, adjusts the shaftI88 having the eccentric trunnions I89. A yoke 322 connects arm 338 withan arm 323, both arms being loosely journalled on shaft 38I. Arm 323 hasa lug 324 urged against a stop 325 (Fig. 33) by a spring 323a connectingthe arm 323 with a stud 3231). Spring 323a urges arm 323counterclockwise in Fig. 33 which means that lug 32I of arm 338 willresist (through the force of spring 323a) clockwise movement due toengagement of lug 328 therewith. Therefore spring 3231: tends to holdrod I I3 and shaft I86 (Fig. 12) in a normal position wherein lever I86(Fig. 10) is located in a normal position relative to cam I2I whichselects pressures according to a normal schedule.

The valve 282 which controls the admission of pressure oil to thecylinder 2' is under joint control by the cam 388 coordinated with thepressure selecting cam I2I and by an aneroid. The aneroid controlcomprises an aneroid bellows 352 having end plates 353 and 354. A rod348 extends from plate 353 through a hole 358 in a wall I of housing 4and carries the pivot pin 291. Rod 348 is maintained in a substantiallyvertical position during its up and down movement by providing it'with apin 34I connected with a lever 342 having a hub 343 (Fig. 32) which,together with a spacer 344, is mounted on a pivot screw 345 retained bya lock nut 346. A spring 541 surrounds rod 040 and bears against lever230 and urges upwardly a washer 343 against a finished surface 049 ofwall "I to provide a seal for the hole 350 so that variations inpressure in housing 4, due to discharge of oil from the cylinder 21I andother cylinders of housing I to which housing 4 is attached, will notmaterially disturb the pressure acting on aneroid 352 which is housed ina chamber between wall SH and the cover 0. The upper plate 054 has athreaded stem 355 passing loosely through a hole in cover 4 and receivesa. nut 054 urged downwardly by a spring 351 against a finished surfaceof cover 0. By turning nut 555, the aneroid can be adjusted verticallyso that valve 200 can be properly located in initial position Asrotation of plate 254 is prevented by a pin 350 attached to the plateand slidable in a hole in the cover 0. The nut 355 is protected by acover 050 attached by a screw 350 to the stem 355. A spring I resiststhe collapsing of bellows 352, the movement of plate 353 toward plate354 being limited by a spacer sleeve 302.

The control mechanism can be disabled by the upward movement of a pin310 received by slot 200 in lever 245. Such movement will cause lever204 to move upward from any position of automatic control to cause valve290 to return to the position shown in Fig. 28A so that cylinder 2" willbe connected with discharge ports 2" and the spring 212 can return thepiston to normal position as shown in Fig. 28A. Pin 310 is attached toarm "I attached to shaft 512 which, as shown in Fig. 2, is operated by alever I13.

Fig. 35, based on altitude and horsepower, shows power linescorresponding to the predetermined schedule of engine speeds andselected pressures. The present gear-shift operating unit is intended toeffect shift from low to high ear according to shift line :r-il. Forpressure selections at 37.5" Hg and higher, shift takes place at aminimum altitude line, for example, 10,500 feet. The shift takes placeat higher altitudes as the pressure selection is decreased from 37.5"Hg. The upper right of Fig. 35 gives a schedule of pressure selectionsand corresponding pressure increases at time of shift. The increasesrange from zero for 29.2 pressure selection and lower to 5.7" for 38.6"pressure selection and back to zero for 44.3 selection or higher. Nopressure increase is neededin the low pressure range. No pressureincrease to a value over 44.3" Hg is permitted on account of possibledetonation due to raising the temperature of the intake air on accountof high speed operation of the auxiliary blower. Hence there is nopressure increase when the pressure selection is 44.3". By withholdingthe shift to high blower until at least a minimum altitude is reached,there is such drop in pressure from a pressure selection in excess of44.3" that the maximum pressure after shift to high blower will notexceed 44.3".

Fig. 28A shows the apparatus in normal or nonoperating condition.Cylinder 2* is vented. Fig. 383 shows the location of cam 000 and camplate III for the pressure selection of 38.6 Hg which can be given thegreatest increase at time of shift into high blower. The roller 3|! oflever III engages the hump 5a of cam surfaces 3l5 of cam plate 3| 0.Valve 200 is about ready to open ports 205. When that altitude isreached which coincides with that point of the shift line :c-u (Fig. 35)common to pressure line 38.6" Hg, the ports 200 will be "cracked open"and piston 21. will nut 350 is turned,

move left causing lever 262 to move into the position shown in Fig. 283and likewise lever 255 due to the snap-action of spring 260. As shiftinto high takes place by the movement of lever 250, lever SIB moves intothe position shown in Fig. 283 thereby causing, through the engagementof its lug 320 with lug 32] of lever 330, such rotary movement of shaftI00 (Figs. 10 and 13) in a counterclockwise direction about the axes oftrunnions I08 as to cause a movement of lever I00 in a counterclockwisedirection while its roller I20 rests on cam I2 I. Lever I00 receives thesame movement as it would have received by rotating the cam I2I into ahigher pressure selecting position. Therefore the intake pressure isincreased although the pressure selecting cam I2l has not been moved.

The variable increase of pressure at time of shift into high blower isdetermined by the contour of cam 3|5 which can be shaped to suit anyrequired schedule of increases.

After the shift into high blower has been made, the plane can climbsubstantially before the critical altitude for high blower is reached.

During descent, when the altitude becomes slightly less than thatscheduled by the shift line :ry, the land 292 of valve 200 is raisedabove the ports 205 and the cylinder 2' becomes vented and the spring212 is released for operation to cause the mechanism to return to thestatus shown in Fig. 28A and the auxiliary blower to return to low-speedoperation.

In the modification shown in Fig. 36, datum cam lever I00 carries a studengageable with a stop "I in the form of a disc integral with a screw402 and eccentric with respect to the axis thereof. Screw 402 isthreaded through a plate 403 attached by screws 404 (Fig. 38) to housingI. A washer 405 is connected with screw 402 by providing it with a flat402a receiving a. flat provided by the hole in the washer. Washer 405has an index 401 pointing to graduations on a plate 408 attached tohousing I. The graduation mark indicated by the index 401 shows themaximum pressure which can be obtained. For example, it is necessary tolimit the maximum pressure to 71.5" Hg, so that the engine will notdetonate, the screw 402 is turned until the index 401 points to the71.5" mark on the dial and a nut 405 threaded on screw 402 is tightenedto secure it in the required position. The eccentric stop 40I is solocated that roller I20 cannot follow the datum cam I2I beyond its 71.5"Hg pressure selecting position. Inthis way, the regulator can beadjusted to meet the requirements of various engines.

A lost-motion connection between lever l0! and lever IN is provided. PinI05 attached to lever I05 connects with a link 410 having a slot 4receiving a pin I03 attached to lever IOI. The normal distance betweenpins I05 and I0 is maintained by a spring 2 connecting these Pins andreceived by a recess 3 in link H0. The yielding connection provided bythe spring H2 is needed in a construction which, for sake of shorteningthe regulator, requires locating the shaft IOI so much closer to theclevis 99 than shown in Fig. 10. It is possible to have a conditionwhen, at the time when cam I2 I is moving counterclockwise to move leverI00 clockwise, clevis 59 is engaging shaft I80. A non-yielding linkbetween lever I00 and lever IOI would distort lever IN. The spring 4I2provides, in effect, a stretchable link whereby the distance betweenpins I05 and I03 can increase while clevis 99 is engaging shaft Insteadof the rotary valve I18 for controlling the propeller pitch governorservo-motor, Fig. 38 shows a slide valve 420 having lands I and 422 forcontrolling. respectively, pressure-oil inlet port 423 and drain port424. Valve 420 is connected by a rod 425 with the movable core orarmature 426 of a solenoid 430 having a fixed core 427, a magnet coil428 and a spring 429 urging the armature toward the right. Normallyinlet 423 is open. and drain 424 is closed. By closing a manuallyoperated switch (not shown) the magnet coil 428 is connected with acurrent source; and'armature 425 and valve- 420 move left in order toblock inlet 423 and to open drain 42 5. Pressure to the left of pistonH3 is relieved; and spring 230 pushes the piston 13 to extreme leftthereby causing the lever 16! to be positioned for highest governedengine speed. In the form shown inFig. 37, the control of the propellergovernor control servo-valve by lever 243 (Fig, 2) is omitted.

The modification of normal speed schedule AB-C (Fig. 34) to give aschedule such as represented by A1-BC, A2-BC, etc., (Fig. 34) can beeffected by t e lever 243 for purposes other than for reducing governedspeed and power output as the load carried by the plane decreases. Forexample, in case of multiple engines each equipped with the resentregulator, the levers 243 may be individually operated in order toequalize the engine speeds.

While the embodiments of the present invention as herein disclosed.constitute preferred forms, it is to be understood that other formsmight be adopted, all coming within the scope sary when the manuallyoperable means is in positions selecting higher pressures, means forcontrolling the servo-motor under joint control by the manually operablemeans and by said element whereby the throttle valve is moved by theservo-motor to compensate for deviatons of intake pressure from selectedpressure, and means for conditioning the servo-motor control means toarrest that movement of the servomotor which would move the throttlevalve past wide-open position when said throttle valve has been movedinto substantially wide-open position.

2. A pressure regulator for a supercharged. internal combustion enginehaving a throttle valve comprising, in combination, manually operablemeans for moving the throttle valve and or selecting an engine intakepressure to be maintained, an engine-intakepressure-sensitiveelenecessary when the manually operable means is in positions selectinghigher pressures, a valve for controlling the servo-motor under jointcontrol by the manually operable means and by said element whereby thethrottle valve is moved 5 by the servo-motor to compensate fordeviations of intake pressure from selected pressure, and meansresponsive to movement of the throttle valve into substantiallywide-open position formoving the servo-motor-control-valve intoequilibrium position thereby arresting that movement of the servo-motorwhich would move the throttle valve past wide-open position.

3. A pressure regulator for a supercharged internalcombustion enginehaving a throttle valve comprising, in combination, manually operablemeans for moving the throttle valve and for selecting an engine intakepressure to be maintained, an engine-intake-pressure-sensitive element,an hydraulic servo-motor capable of adding to the manually-effectedmovement of the throttle valve a movement required to bring the throttlevalve into substantially wide-open position at critical altitude whenthe manually operable means is in a certainlow-pressure-selectingposition and a movement which is greater thannecessary when the manually operable means is in positions selectinghigher pressures, a valve for controlling the servo-motor under jointcontrol by the manually operable means and by said element wh reby thethrottle valve is moved by the servo-motor to compensate for deviationsof intake pressure from selected pressure, and means responsive tomovement of the throttle valve into substantially wide-open position forhydraulically locking the servo-motor.

4. A pressure regulator for a supercharged internal combustion enginehaving a throttle valve and propeller pitch governor comprising, incombination, a manually operated control member, devices operatedthereby for selecting engine intake pressures and engine speedsaccording to a predetermined schedule, manually operable means forvariably modifying the speed schedule effected by the speed selectingdevice while the pressure schedule remains unchanged, anengine-intake-pressure-res-ponsive element, means under control by saidpressure selecting device and said element for positioning the throttlevalve to maintain a selected pressure, and means under control by thespeed setting device for adjusting the setting of the control means forthe propeller pitch governor so as to variably control the engine speedin accordance with the position of said speed setting device.

5. A pressure regulator for a supercharged internal combustion eng nehaving a throttle valve and propeller pitch governor comprising, incombination, a manually operated control member, a pressure selectingcam and a speed selecting 60 cam operated by the member for selectingen-' gine intake pressures and engine speeds to be maintained accordingto predetermined schedules, means supporting the speed selecting cam formovement by the control member and for movement laterally of thedirection of its movement by the control member, manually operable meansfor variably efl'ecting lateral movement of the speed selecting cam inorder to modify the speed schedule, while the pressure schedule remainsunchanged, an englne-intake-pressureresponsive element, means undercontrol of said pressure selecting cam and said element for positioningthe throttle valve to maintain a selected pressure, and means' undercontrol by T the speed setting cam for adjusting the setting

